Nitrogen is a vital chemical element found in all living organisms, constitutes 78% of the air we breath, and is an essential plant nutrient. However, excess nitrogen such as NH.sub.3, nitrite and nitrate, in soil or water causes serious problems.
Some microorganisms are able to reduce nitrate and nitrite to nitrogen gas in a process called "denitrification". This results in nitrogen actually being removed from soil and water, thereby releasing N.sub.2 gas into the air. Denitrification maintains the potability of fresh waters and maintains productivity of land masses due to the fact that high concentrations of nitrate ions are toxic. This is especially true when the land mass has an excessive amount of organic matter present, such as areas where manure is generated from livestock.
Denitrification is absolutely vital to the continued availability of combined nitrogen on the land masses of the earth. Nitrates in topsoil are used by plants as an essential nutrient. However, nitrates are also soluble in water and can leach through the soil and into the ground water or runoff across the soil surface to lakes and streams, depending on the soil texture, permeability and land topography. The potential for leaching or runoff from soil increases when the amount of nitrogen applied to the crop lands exceeds the actual needs of the crop itself. Without denitrification, the earth's supply of nitrogen, would eventually accumulate in the oceans precluding life on the land masses, except for a fringe near the oceans.
Excessive nitrogen in the environment from various sources, such as animal waste, and the process of denitrification are issues of growing concern and interest. Manure management plays a critical role in determining how nitrates impact crop production and environmental pollution. This is especially true since the current trend in the livestock industry is moving away from small farms having 100 head or less of livestock, toward the large mega-producers which have thousands of livestock. This growing trend toward these enormous "mega farms", which raise thousands of livestock per year, result in the daunting problem of handling and disposal of massive amounts of manure. This puts a serious demand on the land the livestock is raised on as well as surrounding lands and nearby water supplies. Megafarms typically raise large numbers of livestock in very close quarters resulting in dense manure generation on a relatively small plot of land. For example, swine production in Minnesota alone generate approximately 11 million tons of manure containing 73,000 tons of nitrogen annually, and Minnesota is not even the top swine producing state.
Manure and other livestock waste has the potential to be either a valuable resource or a major pollutant, depending on its management. When not treated or improperly handled, manure nutrients, primarily nitrogen, are potential pollutants of air and water. Thus, manure management in the livestock industry has recently received a great deal of attention. Focus on this issue has occurred for several reasons. The major reason is recent advancements in science have clarified the connection between manure and pollution. In some situations, declining water quality has been directly linked to poor manure management.
Ground water contamination resulting from nitrate leaching and runoff has serious ramifications. Nitrate contaminated water poses a health risk when it is consumed by humans or animals. Health problems associated with nitrate result primarily after the nitrates enter the body and are converted by bacteria to nitrite. High nitrite levels cause a condition known as methemoglobinemia. Methemoglobinemia, also known as "blue baby syndrome", is due to the conversion of nitrate to nitrite by nitrate reducing bacteria in the gastrointestinal tract. Hemoglobin is converted to a brown pigment, methemoglobin, following oxidation by nitrite of Fe.sup.2+ in hemoglobin to Fe.sup.3+. Since methemoglobin is incapable of binding molecular oxygen, the ultimate result is suffocation. Therefore, high levels of nitrogen in areas in which ground water makes up a large portion of the drinking water is a real and valid danger.
Further, additions of raw or semi-treated manure to a lake or stream will significantly degrade water quality. Manure additions increase the nitrogen and organic matter content of the lakes and streams contributing to excessive algae and aquatic plant growth. This growth has a high oxygen demand resulting in gradual depletion of the water's oxygen supply. This algae and plant bloom adversely affects fish and other aquatic life and has a negative impact on the beneficial use of water resources for drinking or recreation. If oxygen concentrations fall below a critical level, fish and other aquatic species die in massive numbers.
Not only are there human health concerns and danger to area aquatic species, but odor also presents a major problem in raising livestock. Odor issues often create tension between livestock producers and neighbors or entire communities. Because odors are produced during the anaerobic decomposition of manure, the surest way to decrease odors is to provide oxygen to the manure via aeration. However, aeration is not practical, is very expensive and necessitates high energy requirements.
Focus on manure management is the result of the public's increasing environmental concerns. For a majority of the public, the words "manure" and "pollution" have become synonymous. Due to the actual and perceived problems with manure, the public is demanding livestock producers have accountability in regard to manure handling and treatment. In fact, there are an increasing number of federal lawsuits filed against livestock producers claiming that the producers have violated the U.S. Clean Water Act, Clean Air Act and National Pollution Discharge Elimination System Permit Programs. Therefore, manure management and treatment is becoming a major factor in local, national and international livestock production. It is clear that livestock producers must effectively treat their manure and other waste products in order to avoid the aforementioned problems, and possibly even expensive and lengthy lawsuits.
There are many treatment systems currently utilized to handle the massive amounts of manure generated, including liquid-solid separation, composting, oxygen ditches, physical removal, digging deeper lagoons and the like. However, there are many problems and drawbacks associated with each and, on the whole, treatment systems are not typically cost effective.
Liquid-solid separation systems, such as settling basins and mechanical separators, provide a means of separating nutrients from the waste stream. However, the separation of nutrients requires relatively large mechanical separators which can be quite costly and require substantial amounts of energy.
Composting reduces and stabilizes the organic matter, but can require quite a large amount of time in order to properly compost the manure into a uniform, dry and odorless soil conditioner.
Oxidation ditches stabilize and reduce the organic matter in the waste material. However, these systems are relatively uncommon and typically uneconomical due to their high energy demands.
Some mega-producers have resorted to building miles and miles of pipe line in order to physically transport waste material to available land some distance from the farm itself. However, this is a cumbersome method of handling manure as well as an expensive one. Further, neighboring communities are threatened by pipe bursts or leaks.
Other producers have resorted to digging deeper lagoons, as much as 20-25 feet deep, as opposed to the standard 8-10 feet deep lagoon, in order to store waste material. However, the increase in depth dramatically decreases the surface-to-volume ratio, resulting in exceedingly high nitrogen levels.
What is desperately needed in the livestock industry is a waste treatment to reduce harmful nitrogen levels which is economically feasible, technically viable, easy to use and environmentally sound.
The present invention utilizes the natural process of denitrification to reduce nitrogen levels and is less expensive than the prior art treatment methods. Further, this invention does not require long periods of time before it effectively begins to reduce nitrogen levels. This invention also does not require large amounts of energy or specialized equipment, like some of the prior art treatment methods mentioned above. Further, the present invention is simple, easy to use and does not utilize potentially harmful or dangerous chemicals.
Specifically, this novel composition denitrifies harmful nitrogen compounds to nitrogen gasses and is thereby able to significantly reduce nitrogen levels in areas containing large amounts of nitrogen-containing biological waste.